The present invention relates to an ink-jet recording apparatus that includes a recording head for ejecting ink droplets through nozzle openings in response to a print signal, and an ink cartridge used to supply ink to the recording head.
An ink-jet recording apparatus, which includes a recording head and an ink cartridge used to supply ink to the recording head, is so designed that a supply port is formed in the ink cartridge and that, to supplement the supply of ink, the ink cartridge is inserted into or removed from an ink supply needle that communicates with the recording head.
As is shown in FIG. 13, an ink supply needle A is so designed that a filter chamber D is formed by opening a joint area using an ink supply path C that communicates with a recording head B, and that air bubbles, which are generated or have grown in an ink cartridge, or dust, are captured at the filter E and are prevented from flowing into the recording head B.
However, for a recording head for which light colored inks are employed to improve the color print quality, the space around the recording head must be relatively narrow in order for at least six colored inks to be supplied to the recording head, and accordingly, the diameter of the ink needle A must be reduced. As a result, an air bubble F is formed that remains stagnant inside the ink supply needle A and interrupts the supply of ink to the recording head B.
In addition, when a recording head having multiple nozzle openings is employed to increase the recording density and the print quality, the dimensions of the filter E must be increased and the flow path resistance must be reduced in order to smoothly supply a large volume of ink to the recording head. Accordingly, a large space is produced upstream of the filter member, so that the flow rate of ink is reduced there and air bubbles are not discharged. These air bubbles stick to the filter member and increase the flow path resistance. And as a result, they interrupt the supply of ink to the recording head.
Further, when a large air bubble F enters the filter chamber D during the ink loading process, the air bubble F adversely affects the flow if ink, and the difference in the pressures between the upstream and the downstream sides of the filter E is increased.
In particular, for a recording head in which ink carried by a single supply needle branches off to a plurality of ink supply paths C and supplies ink to a plurality of nozzle openings, if the internal face of the filter chamber D is not kept uniformly wet, ink will flow across a wetter portion, and will form an ink flow induction path. Then, when the induction path is so positioned that it can easily communicate with the ink supply path C, if ink flows to the ink supply path C before the filter chamber D is completely filled, the air bubble F will remain in the filter chamber D, regardless of the attraction exerted by the ink, and will be difficult to discharge.
An ink-jet recording apparatus according to the present invention comprises:
a recording head for receiving ink supplied via a first ink supply path and for ejecting ink droplets;
a second ink supply path along which ink is transmitted from an ink cartridge to the first ink supply path; and
a filter which is located at a joint area that forms a communication portion situated between the first ink supply path and the second ink supply path,
wherein ink induction paths are formed at the joint area on the side of the second ink supply path in order to use capillary attraction to induce the flow of ink through the filter.
It is, therefore, one objective of the present invention to provide an ink-jet recording head, wherein the flow of ink to a recording head is not disturbed by air bubbles that are generated during the loading of ink, and wherein ink can be supplied to the recording head while at the same time air bubbles are removed.